Optical coupling devices such as optical connectors and optical ferrules allow light from a one or more waveguides to pass through a first connector to a corresponding set of waveguides of a mating second connector. The mating devices mechanically couple together and align optical elements of the first device with optical elements of the mating device. Optical coupling devices can be used for optical communications in a variety of applications including telecommunications networks, local area networks, data center links, and internal links in computer devices.